V Lisovskiy, J Booth, S Martins - Europhysics letters - страница 2

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At lower gas pressures the plasma density is lower, due to the lower rate of ionising colli­sions, and the sheaths are wider. Again, the sheath thickness first increases with increasing RF voltage. However, the point at which the sheath width saturates and then starts to de­crease occurs at increasingly higher voltages as the pressure is lowered; the transition to a high-current regime occurs later and is less marked. In the multi-valued region of the ex­tinction curves (see the curve at 0.032mTorr in fig. 3), the thickness of sheaths approaches one-half of the inter-electrode gap at high RF power before the sheath thickness saturates, so that the sheaths overlap and the RF discharge is extinguished (at Urf « 300 V in this case).

This paper presents measurements of breakdown and extinction curves for RF capacitive low-pressure discharges in hydrogen and nitrogen. The shape of the extinction curves is similar to that of breakdown curves for the same gas species and gap values. The extinction curves may possess two minima (corresponding to the minima of the Paschen and diffusion-drift branches of the breakdown curves). For large gaps, L> 10 mm, a multi-valued region is observed at low pressure. The increase of the sheath thickness with RF voltage (at sufficient low gas pressure) may be the reason for this. When the sheaths overlap, the RF discharge becomes unstable and extinguishes. The results of a fluid simulation agree with the observed data.

The authors express our gratitude to the UNAXIS France - Displays division, Palaiseau, France for their financial support and for the equipment used in this study.

REFERENCES

[1] Hulburt E. O., Phys. Rev., 20 (1922) 127.

[2] Kirchner F., Ann. Phys. (Leipzig), 77 (1925) 287.

[3] Townsend J. S. and Nethercot W., Philos. Mag., 7 (1929) 600.

[4] Thomson J., Philos. Mag., 10 (1930) 280.

[5] Rohde L., Ann. Phys. (Leipzig), 12 (1932) 569.

[6] Llewellyn Jones F. and Morgan G. D., Proc. Phys. Soc. London, Ser. B, 64 (1951) 560,

574.

[7]  Llewellyn Jones F. and Williams G. G., Proc. Phys. Soc. London, Ser. B, 66 (1953) 17, 345.

[8]   Pateyuk G. M., J. Exp. Theor. Phys., 3 (1956) 14.

[9]   Francis G., Ionization Phenomena in Gases (Butterworths, London) 1960. [10]   Kakuta S., Makabe T. and Tochikubo F., J. Appl. Phys., 74 (1993) 4907. [11]  Kakuta S., Petrovic Z. L., Tochikubo F. and Makabe Т., J. Appl. Phys., 74 (1993) 4923. [12]  Lisovskiy V. A., Tech. Phys., 43 (1998) 526.

[13] Caillier В., Autret D., Lebarq N., Callegari Th., Guillot Ph., Galy J., Pitchford L. C. and Boeuf J. P., Proceedings of the XVI European Conference on Atomic and Molecular Physics in Ionized Gases, Grenoble, France, 14-18 July, 2002, Vol. 1,p.355.

[14]  Lisovskiy V. A. and Yegorenkov V. D., J. Phys. D, 31 (1998) 3349.

[15] Raizer Yu. P., Schneider M. N. and Yatsenko N. A., Radio-Frequency Capacitive Dis­charges (CRC Press, Boca Raton) 1995.


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